The present invention relates to a sand vehicle. More particularly, the present invention relates to a sand vehicle which increases a balance of a main frame and decrease a vibration of the main frame.
Referring to FIGS. 1 and 2, a conventional sand vehicle has a main frame 10, an engine 11 disposed on the main frame 10, a shock absorber 13 disposed on a rear portion of the main frame 10, a rear shaft 12 disposed on the rear portion of the main frame 10, and two rear wheels 14 connected to the rear shaft 12. When a user turns his body rightward or leftward, the engine 11 will deflect rightward or leftward also. Thus the conventional sand vehicle will be overturned because of the instability of the center of gravity. Furthermore, one shock absorber 13 for two rear wheels 14 cannot decrease a vibration of the conventional sand vehicle effectively while the user drives the conventional sand vehicle on an uneven road.
An object of the present invention is to provide a sand vehicle which has an auxiliary frame disposed in a main frame, an engine disposed in the auxiliary frame and a shaft disposed on a rear portion of the auxiliary frame so that the balance of the main frame will not be influence by the auxiliary frame while the auxiliary frame is deflected.
Another object of the present invention is to provide a sand vehicle which has a pair of torsion-resistant elements and a pair of torsion-resistant members to be deformed and restored to their original configurations so that a main frame will not be deflected in order to stabilize the center of gravity of the main frame.
Another object of the present invention is to provide a sand vehicle which has a pair of shock absorbers for a pair of rear wheels in order to decrease a vibration of the sand vehicle effectively while the sand vehicle is driven on an uneven road.
Accordingly, a sand vehicle comprises.a main frame, an auxiliary frame disposed in the main frame, an engine disposed in the auxiliary frame, a rear shaft disposed on a rear portion of the auxiliary frame, a first positioning seat disposed on a front portion of the auxiliary frame, a second positioning seat disposed on the rear portion of the auxiliary frame, a pair of torsion-resistant elements, a pair of sleeves disposed on the first positioning seat to receive the torsion-resistant elements, a pair of connection bars disposed on the rear portion of the auxiliary frame, a connection frame disposed on a rear portion of the main frame, a pair of positioning bars disposed on a front portion of the main frame to match the first positioning seat, the main frame having two rear distal bars, a pair of pivot shafts, a pair of torsion-resistant members, a pair of collars to receive the torsion-resistant members, a pair of connection rods connected to the collars and the pivot shafts, and two rear wheels connected to the rear shaft. Each of the rear distal bars of the main frame has a pivot aperture. Each of the positioning bars has a pivot hole. The torsion-resistant elements are disposed between the positioning bars. A pivot screw rod fastens the torsion-resistant elements and the positioning bars together. The collars are disposed in the second positioning seat. The pivot shafts are disposed on the rear distal bars. Each of the pivot shafts passes through the corresponding pivot aperture of the rear distal bars. A pair of shock absorbers are disposed between the connection frame and the connection bars.